In an old styled telephone set, the ring tone that is used to signal an incoming telephone call is usually produced by a ringer repeatedly striking one or two bells. In a mobile phone, the ringing tone is produced by an electronic buzzer, which produces a pitch of a given frequency according to a value in a data stream representative of a series of musical tones.
Electronically producing music is well known in the art. For example, U.S. Pat. No. 5,753,843 (Fay) discloses a system and process for composing a musical section in response to a user's interaction with a multimedia presentation. As disclosed in Fay, the system includes a composition engine, a performance engine and an arbitrator. The arbitrator provides an interface with an application program running a multimedia presentation. The arbitrator receives parameters from the application program indicative of the user's interaction and the type of music the application program requested in response to the user's interaction. The parameters are passed to the composition engine, which composes a musical section having a chord progression and other data therein. The musical section and the style provided by the arbitrator are used by the performance engine to generate music sequence data for driving a musical instrument. The performance of the musical sequence data by the musical instrument occurs substantially contemporaneously with the user's interaction, which causes the composition of the musical section. The composition engine performs a plurality of functions to compose musical sections, wherein the functions are implemented by a musical template generator and a musical section generator. In the musical template generator, the process of template generation begins by invoking a signpost creation process, which places signpost chord markers in an empty template data structure. After the signpost chord markers have been placed in the template, a second process is invoked to provide embellishment commands in the template. The template is then passed to the musical section generator to add musical content to the template. The musical section generator uses a template retrieved from a data storage to compose the musical section. As disclosed, the method for producing musical sections is based on stored data in combination with a “personality”, which is a data structure for defining a mood. In order to carry out such a method, a large data storage area is necessary for storing all the templates, and a powerful computer is necessary for data processing. As disclosed in Fay, the required computer system has a least an INTEL 386SX processor with at least two megabytes of RAM and at least five megabytes of disc storage space. Thus, while the selection of chords and the selection of personality are useful for a multimedia presentation, they are impractical for generating ringing tones in a small communication device, such as a telephone.
U.S. Pat. No. 5,452,354 (Kyronlahti et al.) discloses a ringing tone apparatus, wherein subscriber identification information is used to generate the ringing tone. As disclosed in Kyronlahti et al., a ringing tone can be generated based on two or more binary digits of the subscriber identification number such as the mobile station identification number (MSIN), mobile identification number (MIN), etc. For example, if the lowest bits of the identification MSIN are described as a string of 11 binary digits D10-D9-D8-D7-D6-D5-D4-D3-D2-D1-D0, this string of digits can be used to specify the parameters necessary for generating a ringing tone as follows: D1 and D0 are used to determine the duration of each ringing tone pulse; D3 and D2 are used to determine the frequency of the ringing tone pulses; D5 and D4 are used to determine the pulse number in one pulse sequence; D7 and D6 are used to determine the number of sequences to be repeated in the ringing tone; and D10, D9 and D8 are used to determine the silence period between pulse sequences. While this tone generation method is useful for producing different ringing tones for different subscribers, the ringing tones may sound too mechanical and may contain musical notes that are not pleasing when played together.
Thus, it is desirable to provide a method to produce a vast range of plausible and pleasing telephone ringing tones, wherein the ringing tones are randomly produced so as to allow a user to select a different ringing tone to signal an incoming telephone call or to indicate the reception of a voice or data message.